MCT or FCT stone are in many costume enchant boxes. Eventually, all costumes in a costume egg can be exchanged to a costume enchant boxes that give those stone. However, this is not the same for job stones. Sorcerer, ranger and sura stones are exclusive for costume enchant boxes 13. If Warpportal still allows 3 costumes in one eggs to be exchanged for one version of costume enchant boxes, it will be extremely difficult to obtain these stones.
Like, now you have 3/10 chances to get box 13. When box 14 comes, it will be 11/12/12/12/13/13/13/14/14/14, so 3/10 chances again. I'm not sure if it is so difficult to obtain those stones like this in other servers. It's absurd.